<!DOCTYPE html>
<html lang="en">
<script>
  var _hmt = _hmt || [];
  (function () {
    var hm = document.createElement("script")
    hm.src = "https://hm.baidu.com/hm.js?c923daf3182a4b0ce01878475080aadc"
    var s = document.getElementsByTagName("script")[0]
    s.parentNode.insertBefore(hm, s)
  })();
</script>

<head>
  <meta charset="UTF-8">
  <title></title>
  <link href="css/style.css" rel="stylesheet">
  <script src="https://cdn.bootcss.com/jquery/2.1.1/jquery.min.js"></script>

</head>
<style>
  body {
    margin: 0;
    overflow: hidden;
    background: black;
  }

  canvas {
    position: absolute;
  }
</style>

<body>
  <div>
    <div id="celebrateContainer"></div>
    <div class="firecrackers"></div>
    <script src="js/bianpao.js"></script>

    <div style="text-align:center;"></div>
    <div class="congratulations">
      <svg viewBox="0 0 100 100">
        <path d="M 0 50 Q 50 30 , 100 50  " id="circle" />
        <text font-size="7" style="letter-spacing:1;" fill="red">
          <textPath xlink:href="#circle">

          </textPath>
        </text>
      </svg>

    </div>
  </div>
  <canvas></canvas>
  <canvas></canvas>
  <canvas></canvas>

  <script>

    function GetRequest () {
      var url = decodeURI(location.search) //获取url中"?"符后的字串
      var theRequest = new Object()
      if (url.indexOf("?") != -1) {
        var str = url.substr(1)
        strs = str.split("&")
        for (var i = 0; i < strs.length; i++) {
          theRequest[strs[i].split("=")[0]] = unescape(strs[i].split("=")[1])
        }
      }
      return theRequest
    }
    class Shard {
      constructor(x, y, hue) {
        this.x = x
        this.y = y
        this.hue = hue
        this.lightness = 50
        this.size = 15 + Math.random() * 10
        const angle = Math.random() * 2 * Math.PI
        const blastSpeed = 1 + Math.random() * 6
        this.xSpeed = Math.cos(angle) * blastSpeed
        this.ySpeed = Math.sin(angle) * blastSpeed
        this.target = getTarget()
        this.ttl = 100
        this.timer = 0
      }
      draw () {
        ctx2.fillStyle = `hsl(${this.hue}, 100%, ${this.lightness}%)`
        ctx2.beginPath()
        ctx2.arc(this.x, this.y, this.size, 0, 2 * Math.PI)
        ctx2.closePath()
        ctx2.fill()
      }
      update () {
        if (this.target) {
          const dx = this.target.x - this.x
          const dy = this.target.y - this.y
          const dist = Math.sqrt(dx * dx + dy * dy)
          const a = Math.atan2(dy, dx)
          const tx = Math.cos(a) * 5
          const ty = Math.sin(a) * 5
          this.size = lerp(this.size, 1.5, 0.05)

          if (dist < 5) {
            this.lightness = lerp(this.lightness, 100, 0.01)
            this.xSpeed = this.ySpeed = 0
            this.x = lerp(this.x, this.target.x + fidelity / 2, 0.05)
            this.y = lerp(this.y, this.target.y + fidelity / 2, 0.05)
            this.timer += 1
          } else
            if (dist < 10) {
              this.lightness = lerp(this.lightness, 100, 0.01)
              this.xSpeed = lerp(this.xSpeed, tx, 0.1)
              this.ySpeed = lerp(this.ySpeed, ty, 0.1)
              this.timer += 1
            } else {
              this.xSpeed = lerp(this.xSpeed, tx, 0.02)
              this.ySpeed = lerp(this.ySpeed, ty, 0.02)
            }
        } else {
          this.ySpeed += 0.05
          //this.xSpeed = lerp(this.xSpeed, 0, 0.1);
          this.size = lerp(this.size, 1, 0.05)

          if (this.y > c2.height) {
            shards.forEach((shard, idx) => {
              if (shard === this) {
                shards.splice(idx, 1)
              }
            })
          }
        }
        this.x = this.x + this.xSpeed
        this.y = this.y + this.ySpeed
      }
    }


    class Rocket {
      constructor() {
        const quarterW = c2.width / 4
        this.x = quarterW + Math.random() * (c2.width - quarterW)
        this.y = c2.height - 15
        this.angle = Math.random() * Math.PI / 4 - Math.PI / 6
        this.blastSpeed = 6 + Math.random() * 7
        this.shardCount = 15 + Math.floor(Math.random() * 15)
        this.xSpeed = Math.sin(this.angle) * this.blastSpeed
        this.ySpeed = -Math.cos(this.angle) * this.blastSpeed
        this.hue = Math.floor(Math.random() * 360)
        this.trail = []
      }
      draw () {
        ctx2.save()
        ctx2.translate(this.x, this.y)
        ctx2.rotate(Math.atan2(this.ySpeed, this.xSpeed) + Math.PI / 2)
        ctx2.fillStyle = `hsl(${this.hue}, 100%, 50%)`
        ctx2.fillRect(0, 0, 5, 15)
        ctx2.restore()
      }
      update () {
        this.x = this.x + this.xSpeed
        this.y = this.y + this.ySpeed
        this.ySpeed += 0.1
      }

      explode () {
        for (let i = 0; i < 70; i++) {
          shards.push(new Shard(this.x, this.y, this.hue))
        }
      }
    }

    console.log(GetRequest('val').val)
    // INITIALIZATION
    const [c1, c2, c3] = document.querySelectorAll('canvas')
    const [ctx1, ctx2, ctx3] = [c1, c2, c3].map(c => c.getContext('2d'))
    let fontSize = 200
    const rockets = []
    const shards = []
    const targets = []
    const fidelity = 3
    let counter = 0
    c2.width = c3.width = window.innerWidth
    c2.height = c3.height = window.innerHeight
    ctx1.fillStyle = '#000'
    const text = '小李，生日快乐，开开心心'
    let textWidth = 99999999

    while (textWidth > window.innerWidth) {
      ctx1.font = `900 ${fontSize--}px Arial`
      textWidth = ctx1.measureText(text).width
    }

    c1.width = textWidth
    c1.height = fontSize * 1.5
    ctx1.font = `900 ${fontSize}px Arial`
    ctx1.fillText(text, 0, fontSize)
    const imgData = ctx1.getImageData(0, 0, c1.width, c1.height)
    for (let i = 0, max = imgData.data.length; i < max; i += 4) {
      const alpha = imgData.data[i + 3]
      const x = Math.floor(i / 4) % imgData.width
      const y = Math.floor(i / 4 / imgData.width)

      if (alpha && x % fidelity === 0 && y % fidelity === 0) {
        targets.push({ x, y })
      }
    }

    ctx3.fillStyle = '#FFF'
    ctx3.shadowColor = '#FFF'
    ctx3.shadowBlur = 25;

    // ANIMATION LOOP
    (function loop () {
      ctx2.fillStyle = "rgba(0, 0, 0, .1)"
      ctx2.fillRect(0, 0, c2.width, c2.height)
      //ctx2.clearRect(0, 0, c2.width, c2.height);
      counter += 1

      if (counter % 15 === 0) {
        rockets.push(new Rocket())
      }
      rockets.forEach((r, i) => {
        r.draw()
        r.update()
        if (r.ySpeed > 0) {
          r.explode()
          rockets.splice(i, 1)
        }
      })

      shards.forEach((s, i) => {
        s.draw()
        s.update()

        if (s.timer >= s.ttl || s.lightness >= 99) {
          ctx3.fillRect(s.target.x, s.target.y, fidelity + 1, fidelity + 1)
          shards.splice(i, 1)
        }
      })

      requestAnimationFrame(loop)
    })()

    // HELPER FUNCTIONS
    const lerp = (a, b, t) => Math.abs(b - a) > 0.1 ? a + t * (b - a) : b

    function getTarget () {
      if (targets.length > 0) {
        const idx = Math.floor(Math.random() * targets.length)
        let { x, y } = targets[idx]
        targets.splice(idx, 1)

        x += c2.width / 2 - textWidth / 2
        y += c2.height / 2 - fontSize / 2

        return { x, y }
      }
    }


  </script>

</body>

</html>